A significant problem in the study of human oral communication concerns how we utilize various types of sensory feedback in controlling the complexly patterned muscle contractions required for speech production. The purpose of this research is to further our understanding of how perioral mechanoreceptor and auditory feedback function in the motor control of lip movements for speech. Auditory receptor function is being studied by means of experiments in which normal auditory feedback is systematically disrupted while measures of lip muscle activity and movement are simultaneously recorded. Perioral mechanoreceptor function is being studied by applying precisely defined mechanical stimuli to the lips during passive and active muscle conditions while EMG potentials from selected facial muscles are recorded. Analysis of these two sets of data should provide significant insight into the manner in which sensory information functions in normal speech production and also aid in the development of speech production models having utility in the diagnosis and treatment of various speech disorders.